VTE Toolkit Chapter Five Venous Disease Coalition Investigation of Suspected VTE VTE Toolkit

Investigation of Suspected DVT Ascending contrast venography Impedance plethysmography Radioactive fibrinogen scan No longer used Doppler ultrasonography (Duplex scan): sensitive and specific for symptomatic proximal DVT CT venography: contrast timing critical MR venography: may be useful for pelvic vein thrombosis VTE Toolkit

Investigation of Suspected DVT Try to never miss acute PROXIMAL DVT Some Doppler labs over-call DVT (especially calf DVT) No one knows if / how calf DVT should be managed Be aware of CLINICAL-IMAGING DISCORDANCE (the clinical features don’t fit with the imaging results) VTE Toolkit

Clinical Predictive Model for DVT Active cancer < 6 mos 1 Paralysis, paresis, recent plaster cast 1 Bedridden > 3 d or major surgery < 1 mo 1 Localized tenderness along deep vein 1 Entire leg swollen 1 Calf swelling 3 cm > asymptomatic side 1 Pitting edema symptomatic leg 1 Collateral superficial veins 1 Alternative diagnosis > likely -2 Low = < 0 Mod = 1-2 High = > 3 Wells - Lancet 1997;350:1795 VTE Toolkit

D-dimer in Suspected VTE D-dimers are degradation products resulting from the action of plasmin on fibrin The presence of D-dimer indicates initiation of blood clotting but many conditions other than DVT give a positive D-Dimer test result Therefore, a positive D-dimer does NOT rule in DVT, but a negative D-dimer can help exclude the diagnosis D-dimer may be useful in outpatients with low pre-test probability for VTE as part of a formal algorithm VTE Toolkit

Compression Doppler Ultrasound VTE Toolkit

Compression Doppler Ultrasound Without Compression With Compression VTE Toolkit

VTE Toolkit Treat Stop Suspected DVT Doppler Ultrasound (DUS) DUS demonstrates DVT DUS negative Low clinical prob or alternative Dx reasonable DVT suspicion remains Treat Stop Repeat DUS in 5-7 days VTE Toolkit

VTE Toolkit Suspected DVT in an Outpatient D-dimer Proximal DUS DVT Clinical probability assessment Low Moderate-High D-dimer Proximal DUS Negative Positive Negative Positive DVT excluded Treat stop repeat DUS 5-7 d use D-dimer VTE Toolkit

Suspected DVT in an Inpatient Proximal Doppler ultrasound Proximal DUS negative DUS demonstrates proximal DVT Continue DVT prophylaxis Treat VTE Toolkit

CT Can Diagnose Proximal DVT VTE Toolkit

Investigation of Suspected PE No diagnostic value of blood gases in suspected PE V/Q scans: At least 60% are non-diagnostic Consider in some patients with renal dysfunction or severe contrast allergy Reasonable option for outpatients with normal CXR, and either very high probability of PE or low probability Role in pregnancy and young women (because of reduced radiation dose) CT Pulmonary Angiogram (“Spiral CT”): Accurate for segmental or larger PE Accuracy and clinical relevance of sub-segmental abnormalities is uncertain VTE Toolkit

Wells Clinical Predictive Model for PE History Previous proven DVT or PE 1.5 Immobilization > 3 d or surgery prev. month 1.5 Malignancy (current or < 6 mos.) 1 Hemoptysis 1 Physical exam Signs of possible DVT (leg swelling, tenderness 3 HR > 100 1.5 Alternative diagnosis PE as likely or more likely than alternative 3 Pre-test probability score VTE High >6.0 41-50% Moderate 2.0-6.0 16-19% Low <2.0 1-2% Wells - Thromb Haemost (2000) Ann Intern Med (2001) VTE Toolkit

Revised Geneva Score for PE Assessment based on 8 clinical variables (not on clinical judgment) Points Age > 65 1 Surgery/fracture past month 2 Active cancer 2 Hemoptysis 2 Previous DVT/PE 3 Unilateral leg pain 3 HR 75-94 3 HR > 95 5 Unilat. edema + tenderness 4 PE Risk Points prevalence Low 0-3 8 % Intermediate 4-10 29 % High > 11 74 % Le Gal – Ann Intern Med 2006;144:165 VTE Toolkit

Highly Abnormal Perfusion Scan VTE Toolkit

CT Pulmonary Angiogram VTE Toolkit

VTE Toolkit

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Subsegmental “Something” Is it PE? Is it important? VTE Toolkit

VTE Toolkit ? Suspected PE in an Outpatient D-dimer CTPA PE excluded Clinical probability assessment Low Moderate High ? D-dimer CTPA Negative Positive CTPA: no PE CTPA: nondiag CTPA: definite PE* PE excluded Treat PE excluded DUS of prox veins repeat CTPA *At least segmental filling defect and “reasonable” clinical suspicion VTE Toolkit

VTE Toolkit CTPA Suspected PE in an Inpatient Continue Treat Definite* PE No definite PE Continue prophylaxis Treat *At least segmental filling defect and “reasonable” clinical suspicion VTE Toolkit

Venous Disease Coalition www.vasculardisease.org/venousdiseasecoalition/ VTE Toolkit